5252 is just a number used to calculate HP. HP = Displacement, bore and stroke and cam profile dictate what rpm your peak TQ will come in at.Its 1 word, this one word has been known to be non existent in the import world since the dawn of imports, its what separates the men from the boys (or the men from the men with a lot of extra scratch to blow on a lesser product). This word I speak of is called TORQUE. 6.4l V8 has WAY more torque which is usable power below 5252 rpms, with this power down lower, naturally it needs less RPM to perform a perfect launch. Now the imports that rev to 8k rpm dont hit their max torque till after 5252 rpms which means to get the power to the wheels the rpms have to be higher.
This 5252 number is the magic number that dictates if the car has more torque than horsepower or visa-versa.
Even then with the gtr if you use this launch control your kissing your warranty good by on a 20k dollar transmission, so YES, a lot probably has to do with drivetrain longevity, taking the option and the argument for warranty repairs more out of the customers hands by being a little more gentle.